Plunger switch



March 2, 1948 E. W. RICKMEYER PLUNGER SWITCH Filed Jan. 20, 1945 l gli zalf,"

Patented Mar. 2, 1948 2.436,11 PLUNGER swrrcn Ernst Walter Rickmeyer, Elmhurst, Ill., assignor to Jefferson Electric Company, Bellwood, Ill., a corporation of Illinois Application January zo, 1945, serial No. 513,656

2 claims. (ci. zoo- 159) This invention relates to an improved construction for plunger type switches.

That particular embodiment of my inventicn herein shown and described is directed to a plunger type switch which is biased into closed circuit position, this type of switch being commonly used in connection with doors, such as refrigerator doors, automobile doors, and the like, wherein it is desired to automatically close the light switch when the door is open.

My invention relates specifically to a novel and improved arrangement of parts such that a metal housing may be used for the switch, the current carrying parts being insulated from the housing and from each other.

It is an object of this invention to provide an improved switch construction in which the parts are fully insulated.

It is a further object to provide an improved construction for a spring biased plunger switch which may be manufactured at low cost, and which is easy to assemble.

Another object is to provide an improved switch construction which is mounted in a metal housing which embodies means for carrying a slidable plunger, together with a spring for biasing the plunger into closed circuit position.

Still another object of my invention is to provide novel means for mounting the contact members of a switch in a spaced position so that they may be engaged by a bridge member carried by a suitable plunger.

Other objects, features and advantages of my invention will appear as the description proceeds.

With reference now to the drawings, which illustrate a preferred embodiment of my invention, and in which like reference numerals designate like parts- Fig. 1 is a sectional elevation of a plunger type switch;

Fig. 2 is a section taken along line 2-2 of Fig. 1:

Fig. 3 is a section taken along line 3-3 of Fig. 1;

Fig. 4 is a detail of the contact mounting member;

Fig. 5 is a detail of the contact bridging member;l and Fig. 6 illustrates a modied form of construction for the insulating lining.

'I'he switch comprises a metal shell I0 which forms a housing, together with a reciprocating plunger I3 which extends through the top wall of the shell and is adapted to be depressed in order to break the circuit through the switch.

The shell I0 has an opening for the plunger, in which opening is disposed a collar II, the collar having a downwardly projecting skirt which is spun around the edge of the opening in the shell, as indicated by reference numeral I2. The collar is of suillclent length so that the plunger is substantially free-from lateral movement; that is, the plunger does not wobble in the collar.

The open end of shell I0 is closed by a base member I4 formed of suitable insulating material, such as a phenolic condensation product, either laminated or molded or, fiber. The side walls of the shell I0 have downwardly depending lugs I5 which are bent over on to the base I4 to hold it in position.

The plunger I3 is provided with a flange I S which engages the shell I0 to limit its upward motion. A contact bridging member Il, made of a suitable conductor, is secured to the under side of flange I6. The plunger I3 includes a depending portion of reduced diameter which is surrounded by a spring I9. 'I'he lower end of spring I9 is received in a cup 2liy the position of the latter being determined by an embossing 2| formed in the base I4.

It will be seen that the cup 20 and the depending portion I8 conilne the ends of the spring, and prevent any lateral displacement thereof which might lead to a short circuiting of the parts.

L-shaped contact strips 22 and 2'3 are disposed within the shell I 0, the ends of each extending through suitable slots in the base I4. The upper ends of the contact strips are provided with contact points 24 and 25. respectively, which extend downwardly into such a position that they may be engaged by the contact bridging member I 1 when the plunger I3 is in its uppermost position.

The contact strips 22 and 23 are insulated from the interior surface of the shell I0 by an insulating lining. This lining is preferably made up of a plurality of sheets of insulating material, such as vulcanized fiber, and includes an apertured sheet 23 for the top of the shell, sheets 21 and 28 for the end walls thereof, and sheets 29 and 30 for the side walls thereof. Thus the interior of the shell is completely lined with insulating material, and the contact strips 22 and 23 are separated from the shell by such insulating material.

An alternative form in which the lining may be constructed is shown in Fig. 6, wherein the insulating members 2l', 28', 29' and 30' are formed in an integral sheet 33 which may be folded along the fold lines 33 which separate the various portions.

The upper portions of the contact strips 22 and 23 are mounted in a contact mounting member d i. As shown in Figs. 1 and 4, the mounting member 3i is provided with two recessed portions 32 in which recessed portions are formed slots 3B and circular apertures 34. The vertical portions of the contact strips 22 and 23 extend through the slots 33 and are held thereby in spaced relationship. The contact points 24 and 25 extend down wardly through the circular apertures 8d so that they may be engaged by the contact bridging member I1 to close the circuit,

The lower ends oi' the contact members 22 and 23 are held in spaced position by the apertured base I4. The contact strips are also provided with inwardly extending tongues iii and di which abut against the base member l, thereby preventing any vertical movement of the contact strips. Thus the contact strips are maintained in spaced position both at their upper and lower ends, and the cooperation between the contact points 24 and 25 and the circular apertures 3d effectively serves to prevent any twisting of the contact members in the slots 33.

Contact bridging member II is provided with side extensions 35, the edges of which are curled as indicated by reference numeral 36 so as to provide a low friction sliding contact with the lining sections 29 and 30. These side extensions 35 also tend to prevent any lateral motion or wobble of the plunger I3. The contact bridging member I1 also embodies end portions 31 which contact the contact points 24 and 25. The operation of the switch has been pointed out above in connection with the description of the various parts thereof.

One of the main advantages of this switch is the ease with which it may be assembled. After the collar II has been spun onto the shell Ill, the insulating portion 26 is inserted, and then the contact spacer member 3l into which the contact strips 22 and 23 havealready been placed. Then the liner portions Y2'I, 28, 29 and 30 are inserted, and the plunger and contact bridging member assembly are inserted. The spring i9, the cup 20 and the insulating base Il are then placed in position, and the lugs I are bent over the latter, thereby completing the assembly. l

Although only a, preferred form of this invention has been shown and described herein, it is apparent that many modications and changes may be made therein without departing from the spirit of the invention.

- housing having a closed top. a base therefor, an

insulating lining for said housing. a plunger ex.- tending through said top, means to bias said plunger upwardly, a bridging member carried by said plunger, contact members adapted to be ensaged by said bridging member when said plunger is in its extended position, Lshaped conducting strips having vertically extending portions disposed along said insulating lining and extending -through said base member and having horizontally extending portions on which said contact members are carried, and a contact mounting member at the top of said housing provided with apertures through which said strips and contact members extend for maintaining said strips and contact members in spaced positions at opposite sides of said plunger, said horizontally disposed portion being confined between the upper surface of said contact mounting member and the insulating lining adjacent the closed top .of said housing.

2. A plunger type switch comprising a metal housing having a top wall, a base therefor, an insulating lining for` the side walls oi said housing, a plunger extending through said top wall, means to bias said plunger upwardly, a contact engaging member carried by said plunger, contact members adapted to be engaged by said contact engaging member when said plunger is in its extended position, and a contact mounting member at the top of said housing provided with apertures through which said contact members extend for maintaining said contact members in spaced positions at opposite sides of said plunger, said contact mounting member being conned between the upper edges oi said insulating lining and the top oi said housing.

MNST WALT@ RICEWEYER.

RmENClES @WEEE The following references are of record in the le of this patent:

' 'skim STATES PATENTS Roeder s Dec. 10, 1940 

